Presonus 2626 Bypass Preamps?

m98ter

New member
When looking at the user manuals for the Quantum versus the new Quantum 2626, I'm seeing a different explanation of what the TRS line connections do. The quantum says this:

"When a TRS is connected, the preamp is bypassed and the input signal is sent directly to the ADC"

Which is what I would like to happen with the 2626, but it says:

"When a device is plugged into the Line input, the mic preamp is bypassed, and the signal is routed to the instrument preamplifier stage."

Which is the same thing it says about the Mic/Instrument inputs 1 and 2 on the same unit? Is this is a typo? I assumed those line inputs would just go straight to the ADC as well? I was hoping to use the 2626 with some outboard pres and totally bypass its preamps, which it doesn't sound like it's doing if the manual is correct? Any clarification? Thanks.
 

bouldersoundguy

Well-known member
I suspect the front panel inputs for channels 1 and 2 are meant for convenient connection of a guitar and so have an appropriate preamp stage ahead of the ADC. There's a pair of "Line Return" inputs on the back for channels 1 and 2 that might function more like the channels 3-8 line inputs on the front.

I would feed signal into the various 1/4" inputs and see if the gain knobs do anything. If they do then you know there's at least some circuitry between the input and the ADC. I can't say for sure in this case, but in most cases where I've been able to see a block diagram for affordable gear, the line input is just padded down and fed to the mic preamp. That said, if the mic preamps are fairly neutral then the tone of a boutique preamp should still come through well enough.
 

m98ter

New member
I actually don't have the interface yet. The ability to go straight to the ADC is something I assumed existed within this unit, but time will tell. I've messaged presonus. If not, I may have to look at the original quantum, or maybe even the lower priced 1810c. It has four TRS line ins that don't have gain knobs, and the manual explicitly states they go straight to the ADC.
 

gecko zzed

Grumpy Mod
The 2626 has broadly the same configuration as the Firepod. Channels 1 & 2 are for mike or instrument, therefore a pre-amp stage is involved for both. CHannels 3 to 8 or mike or line, so XLR will go through a mike preamp stage, whereas TRS will bypass that.

Like, the Firepod, the 2626 has provision for inserts on channels 1 & 2, and were you to need it, the returns could be used for two extra line ins.
 

m98ter

New member
The 2626 has broadly the same configuration as the Firepod. Channels 1 & 2 are for mike or instrument, therefore a pre-amp stage is involved for both. CHannels 3 to 8 or mike or line, so XLR will go through a mike preamp stage, whereas TRS will bypass that.

Like, the Firepod, the 2626 has provision for inserts on channels 1 & 2, and were you to need it, the returns could be used for two extra line ins.

Yeah, I'm sure it bypasses the pre, but what I can't figure out is if goes straight to the ADC or not. My sweetwater guy is trying to help me figure it out too, but he said, "I know on some interfaces in the past they've "bypassed" the pre but it technically still hit the circuit and gain could be applied to it". Which is what I"m wondering if this is the case. In that scenario, I could still raise or lower the volume of the TRS in. I'm fairly new at this, but I just dropped a boatload of cash on some outboard, and would like to hear it exactly as it is leaving that outboard and not have another gain in the middle. Unless that totally doesn't matter? Set it at zero? Adjust the gain from the outboard?
 

LemonTree

Suck 'em and see!
Don't know if anyone can help here. I'm about to pull the trigger on the quantum 2626 but in th online manual it says both headphone outs mirror the main outs. Can I change that with software to set up cue mixes from my daw? (Cubase 10.5) ?
 

ecc83

Well-known member
The idea that any line input goes "straight to the ADC" is a false one.

An ADC's input can easily be blown from a standard op amp running at even 12V dual rails. There is also usually a precise CR network feeding the converter and so an analogue 'buffer' must drive that.

The result of all that means that the line input must actually ATTENUATE the incoming signal for voltages much above 0dBu or 3V peak to peak. The design of this "pre amplifier" is therefore quite a determining factor as it has a massive influence on the noise levels.

Dave.
 

lkool

New member
Input 1&2 both a preamp out and line return. If you are using an external preamp, the ideal input is to use the line return of one of these channels.
 
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